This application relates to fiber devices, and more particularly, to fiber tap monitors and fiber power control devices in fiber devices or systems such as fiber communication systems.
Optical monitoring of one or more optical signals is desirable in many applications. In general, a fraction of an optical signal is sampled by using a power splitter or tap as a monitor beam and is directed into an optical detector to determine the power level and other information of the signal. The monitor beam may be only a small fraction of the signal so that the sampling does not significantly affect the power level of the signal. Such optical monitoring may be implemented in fiber communication networks to monitor optical signals at selected locations.
In addition, a power level of an optical signal may need to be reduced to meet certain operational requirements. For example, in fiber communication systems, it may be desirable to maintain the power levels of different WDM channels at the about the same power level. If a channel is found to be higher than the desired channel power beyond a tolerance level, the power of that channel may be attenuated. This attenuation may be achieved by using a variable optical attenuator (VOA) to provide a variable power attenuation according to the amount of deviation beyond the tolerance level. As another example, an optical signal may be attenuated to keep the signal power within a detection dynamic range of an optical detector.
Therefore, there is a need for devices that combine optical monitoring and optical attenuation.